From 8e6a96266ae4617bc14faa1155fc35d1319fa431 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 8 Jun 2007 10:29:29 +0000 Subject: [PATCH] rt-mutex: Fix chain walk early wakeup bug Alexey Kuznetsov found some problems in the pi-futex code. One of the root causes is: When a wakeup happens, we do not to stop the chain walk so we we follow a non existing locking chain. Drop out when this happens. Cc: Alexey Kuznetsov Signed-off-by: Thomas Gleixner Acked-by: Ingo Molnar Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman --- kernel/rtmutex.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index 21ebe7612f83a..17d28ce20300d 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -212,6 +212,19 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task, if (!waiter || !waiter->task) goto out_unlock_pi; + /* + * Check the orig_waiter state. After we dropped the locks, + * the previous owner of the lock might have released the lock + * and made us the pending owner: + */ + if (orig_waiter && !orig_waiter->task) + goto out_unlock_pi; + + /* + * Drop out, when the task has no waiters. Note, + * top_waiter can be NULL, when we are in the deboosting + * mode! + */ if (top_waiter && (!task_has_pi_waiters(task) || top_waiter != task_top_pi_waiter(task))) goto out_unlock_pi; -- 2.47.2